In the field of therapeutic electrical stimulation, it is often desirable to provide electrical connection of more than one lead to a single connection port of a medical device. In particular, in the field of cardiac pacing, it is sometimes necessary to provide electrical connection of two leads to a single connection port of an IMD, e.g. a cardiac pacemaker or implantable cardioverter defibrillator, such that stimulation pulses may be delivered to more than one cardiac site or across a desired vector.
Medical lead connectors have been standardized in the industry. For example IS-1 pacing/sensing connectors are available in unipolar or bipolar configurations, including one or two electrical contacts, respectively, for making connection between a unipolar pace/sense electrode or a bipolar pace/sense electrode pair and an IMD; DF-1 connectors are available for making a high-voltage connection between an IMD and a defibrillation electrode via a single a single electrical contact. Other contemplated standards define connectors for making both high-voltage and low-voltage connections between an IMD and multiple electrodes; one such standard defines a connector including two high voltage contacts and two low voltage contacts, effectively combining two unipolar DF-1 connectors and a bipolar IS-1 connector into a single connector in order to provide electrical coupling to two high-voltage electrodes and a bipolar pace/sense electrode pair carried on a single, quadripolar lead for pacing and defibrillating the heart.
Clinical experience has shown that, in some patients, an acceptable defibrillation threshold cannot be reached using a single lead. In these patients, it becomes necessary to implant more than one lead in order to create an effective vector for the delivery of defibrillation energy. It is therefore desirable to provide means allowing connection of two connectors, each including a high voltage contact, to a single connector port of an IMD.